/*  This file is part of the Vc library. {
Copyright © 2018 Matthias Kretz <kretz@kde.org>

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the names of contributing organizations nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

}*/

#include <experimental/simd>
#include <initializer_list>
#include <random>
#include <cfenv>

template <class T, class A>
  std::experimental::simd<T, A>
  iif(std::experimental::simd_mask<T, A> k,
      const typename std::experimental::simd_mask<T, A>::simd_type& t,
      const std::experimental::simd<T, A>& f)
  {
    auto r = f;
    where(k, r) = t;
    return r;
  }

template <class V>
  V
  epilogue_load(const typename V::value_type* mem, const std::size_t size)
  {
    const int rem = size % V::size();
    return where(V([](int i) { return i; }) < rem, V(0))
	     .copy_from(mem + size / V::size() * V::size(),
			std::experimental::element_aligned);
  }

template <class V, class... F>
  void
  test_values(const std::initializer_list<typename V::value_type>& inputs,
	      F&&... fun_pack)
  {
    for (auto it = inputs.begin(); it + V::size() <= inputs.end();
	 it += V::size())
      {
	[](auto...) {
	}((fun_pack(V(&it[0], std::experimental::element_aligned)), 0)...);
      }
    [](auto...) {
    }((fun_pack(epilogue_load<V>(inputs.begin(), inputs.size())), 0)...);
  }

template <class V>
  struct RandomValues
  {
    using T = typename V::value_type;
    static constexpr bool isfp = std::is_floating_point_v<T>;
    const std::size_t count;

    std::conditional_t<std::is_floating_point_v<T>,
		       std::uniform_real_distribution<T>,
		       std::uniform_int_distribution<T>>
      dist;

    const bool uniform;

    const T abs_max = std::__finite_max_v<T>;

    RandomValues(std::size_t count_, T min, T max)
    : count(count_), dist(min, max), uniform(true)
    {
      if constexpr (std::is_floating_point_v<T>)
	VERIFY(max - min <= std::__finite_max_v<T>);
    }

    RandomValues(std::size_t count_)
    : count(count_), dist(isfp ? 1 : std::__finite_min_v<T>,
			  isfp ? 2 : std::__finite_max_v<T>),
      uniform(!isfp)
    {}

    RandomValues(std::size_t count_, T abs_max_)
    : count(count_), dist(isfp ? 1 : -abs_max_, isfp ? 2 : abs_max_),
      uniform(!isfp), abs_max(abs_max_)
    {}

    template <typename URBG>
      V
      operator()(URBG& gen)
      {
	if constexpr (!isfp)
	  return V([&](int) { return dist(gen); });
	else if (uniform)
	  return V([&](int) { return dist(gen); });
	else
	  {
	    auto exp_dist
	      = std::normal_distribution<float>(0.f,
						std::__max_exponent_v<T> * .5f);
	    return V([&](int) {
		     const T mant = dist(gen);
		     T fp = 0;
		     do {
		       const int exp = exp_dist(gen);
		       fp = std::ldexp(mant, exp);
		     } while (fp >= abs_max || fp <= std::__denorm_min_v<T>);
		     fp = gen() & 0x4 ? fp : -fp;
		     return fp;
		   });
	  }
      }
  };

static std::mt19937 g_mt_gen{0};

template <class V, class... F>
  void
  test_values(const std::initializer_list<typename V::value_type>& inputs,
	      RandomValues<V> random, F&&... fun_pack)
  {
    test_values<V>(inputs, fun_pack...);
    for (size_t i = 0; i < (random.count + V::size() - 1) / V::size(); ++i)
      {
	[](auto...) {}((fun_pack(random(g_mt_gen)), 0)...);
      }
  }

template <class V, class... F>
  void
  test_values_2arg(const std::initializer_list<typename V::value_type>& inputs,
		   F&&... fun_pack)
  {
    for (auto scalar_it = inputs.begin(); scalar_it != inputs.end();
	 ++scalar_it)
      {
	for (auto it = inputs.begin(); it + V::size() <= inputs.end();
	     it += V::size())
	  {
	    [](auto...) {
	    }((fun_pack(V(&it[0], std::experimental::element_aligned),
			V(*scalar_it)),
	       0)...);
	  }
	[](auto...) {
	}((fun_pack(epilogue_load<V>(inputs.begin(), inputs.size()),
		    V(*scalar_it)),
	   0)...);
      }
  }

template <class V, class... F>
  void
  test_values_2arg(const std::initializer_list<typename V::value_type>& inputs,
		   RandomValues<V> random, F&&... fun_pack)
  {
    test_values_2arg<V>(inputs, fun_pack...);
    for (size_t i = 0; i < (random.count + V::size() - 1) / V::size(); ++i)
      {
	[](auto...) {}((fun_pack(random(g_mt_gen), random(g_mt_gen)), 0)...);
      }
  }

template <class V, class... F>
  void
  test_values_3arg(const std::initializer_list<typename V::value_type>& inputs,
		   F&&... fun_pack)
  {
    for (auto scalar_it1 = inputs.begin(); scalar_it1 != inputs.end();
	 ++scalar_it1)
      {
	for (auto scalar_it2 = inputs.begin(); scalar_it2 != inputs.end();
	     ++scalar_it2)
	  {
	    for (auto it = inputs.begin(); it + V::size() <= inputs.end();
		 it += V::size())
	      {
		[](auto...) {
		}((fun_pack(V(&it[0], std::experimental::element_aligned),
			    V(*scalar_it1), V(*scalar_it2)),
		   0)...);
	      }
	    [](auto...) {
	    }((fun_pack(epilogue_load<V>(inputs.begin(), inputs.size()),
			V(*scalar_it1), V(*scalar_it2)),
	       0)...);
	  }
      }
  }

template <class V, class... F>
  void
  test_values_3arg(const std::initializer_list<typename V::value_type>& inputs,
		   RandomValues<V> random, F&&... fun_pack)
  {
    test_values_3arg<V>(inputs, fun_pack...);
    for (size_t i = 0; i < (random.count + V::size() - 1) / V::size(); ++i)
      {
	[](auto...) {
	}((fun_pack(random(g_mt_gen), random(g_mt_gen), random(g_mt_gen)),
	   0)...);
      }
  }

#if __GCC_IEC_559 < 2
// Without IEC559 we consider -0, subnormals, +/-inf, and all NaNs to be
// invalid (potential UB when used or "produced"). This can't use isnormal (or
// any other classification function), since they know about the UB.
template <class V>
  typename V::mask_type
  isvalid(V x)
  {
    using namespace std::experimental::parallelism_v2;
    using namespace std::experimental::parallelism_v2::__proposed;
    using T = typename V::value_type;
    if constexpr (sizeof(T) <= sizeof(double))
      {
	using I = rebind_simd_t<__int_for_sizeof_t<T>, V>;
	const I abs_x = __bit_cast<I>(abs(x));
	const I min = __bit_cast<I>(V(std::__norm_min_v<T>));
	const I max = __bit_cast<I>(V(std::__finite_max_v<T>));
	return static_simd_cast<typename V::mask_type>(
		 __bit_cast<I>(x) == 0 || (abs_x >= min && abs_x <= max));
      }
    else
      {
	const V abs_x = abs(x);
	const V min = std::__norm_min_v<T>;
	// Make max non-const static to inhibit constprop. Otherwise the
	// compiler might decide `abs_x <= max` is constexpr true, by definition
	// (-ffinite-math-only)
	static V max = std::__finite_max_v<T>;
	return (x == 0 && copysign(V(1), x) == V(1))
		 || (abs_x >= min && abs_x <= max);
      }
  }

#define MAKE_TESTER_2(name_, reference_)                                       \
  [&](auto... inputs) {                                                        \
    ((where(!isvalid(inputs), inputs) = 1), ...);                              \
    const auto totest = name_(inputs...);                                      \
    using R = std::remove_const_t<decltype(totest)>;                           \
    auto&& expected = [&](const auto&... vs) -> const R {                      \
      R tmp = {};                                                              \
      for (std::size_t i = 0; i < R::size(); ++i)                              \
	tmp[i] = reference_(vs[i]...);                                         \
      return tmp;                                                              \
    };                                                                         \
    const R expect1 = expected(inputs...);                                     \
    if constexpr (std::is_floating_point_v<typename R::value_type>)            \
      {                                                                        \
	((where(!isvalid(expect1), inputs) = 1), ...);                         \
	const R expect2 = expected(inputs...);                                 \
	((FUZZY_COMPARE(name_(inputs...), expect2) << "\ninputs = ")           \
	 << ... << inputs);                                                    \
      }                                                                        \
    else                                                                       \
      ((COMPARE(name_(inputs...), expect1) << "\n" #name_ "(")                 \
       << ... << inputs)                                                       \
	<< ")";                                                                \
  }

#define MAKE_TESTER_NOFPEXCEPT(name_)                                          \
  [&](auto... inputs) {                                                        \
    ((where(!isvalid(inputs), inputs) = 1), ...);                              \
    using R = std::remove_const_t<decltype(name_(inputs...))>;                 \
    auto&& expected = [&](const auto&... vs) -> const R {                      \
      R tmp = {};                                                              \
      for (std::size_t i = 0; i < R::size(); ++i)                              \
	tmp[i] = std::name_(vs[i]...);                                         \
      return tmp;                                                              \
    };                                                                         \
    const R expect1 = expected(inputs...);                                     \
    if constexpr (std::is_floating_point_v<typename R::value_type>)            \
      {                                                                        \
	((where(!isvalid(expect1), inputs) = 1), ...);                         \
	std::feclearexcept(FE_ALL_EXCEPT);                                     \
	asm volatile("");                                                      \
	auto totest = name_(inputs...);                                        \
	asm volatile("");                                                      \
	((COMPARE(std::fetestexcept(FE_ALL_EXCEPT), 0) << "\n" #name_ "(")     \
	 << ... << inputs)                                                     \
	  << ")";                                                              \
	const R expect2 = expected(inputs...);                                 \
	std::feclearexcept(FE_ALL_EXCEPT);                                     \
	asm volatile("");                                                      \
	totest = name_(inputs...);                                             \
	asm volatile("");                                                      \
	((COMPARE(std::fetestexcept(FE_ALL_EXCEPT), 0) << "\n" #name_ "(")     \
	 << ... << inputs)                                                     \
	  << ")";                                                              \
	((FUZZY_COMPARE(totest, expect2) << "\n" #name_ "(") << ... << inputs) \
	  << ")";                                                              \
      }                                                                        \
    else                                                                       \
      {                                                                        \
	std::feclearexcept(FE_ALL_EXCEPT);                                     \
	asm volatile("");                                                      \
	auto totest = name_(inputs...);                                        \
	asm volatile("");                                                      \
	((COMPARE(std::fetestexcept(FE_ALL_EXCEPT), 0) << "\n" #name_ "(")     \
	 << ... << inputs)                                                     \
	  << ")";                                                              \
	((COMPARE(totest, expect1) << "\n" #name_ "(") << ... << inputs)       \
	  << ")";                                                              \
      }                                                                        \
  }

#else

#define MAKE_TESTER_2(name_, reference_)                                       \
  [&](auto... inputs) {                                                        \
    const auto totest = name_(inputs...);                                      \
    using R = std::remove_const_t<decltype(totest)>;                           \
    auto&& expected = [&](const auto&... vs) -> const R {                      \
      R tmp = {};                                                              \
      for (std::size_t i = 0; i < R::size(); ++i)                              \
	tmp[i] = reference_(vs[i]...);                                         \
      return tmp;                                                              \
    };                                                                         \
    const R expect1 = expected(inputs...);                                     \
    if constexpr (std::is_floating_point_v<typename R::value_type>)            \
      {                                                                        \
	((COMPARE(isnan(totest), isnan(expect1)) << #name_ "(")                \
	 << ... << inputs)                                                     \
	  << ") = " << totest << " != " << expect1;                            \
	((where(isnan(expect1), inputs) = 0), ...);                            \
	((FUZZY_COMPARE(name_(inputs...), expected(inputs...))                 \
	  << "\nclean = ")                                                     \
	 << ... << inputs);                                                    \
      }                                                                        \
    else                                                                       \
      ((COMPARE(name_(inputs...), expect1) << "\n" #name_ "(")                 \
       << ... << inputs)                                                       \
	<< ")";                                                                \
  }

#define MAKE_TESTER_NOFPEXCEPT(name_)                                          \
  [&](auto... inputs) {                                                        \
    std::feclearexcept(FE_ALL_EXCEPT);                                         \
    auto totest = name_(inputs...);                                            \
    ((COMPARE(std::fetestexcept(FE_ALL_EXCEPT), 0) << "\n" #name_ "(")         \
     << ... << inputs)                                                         \
      << ")";                                                                  \
    using R = std::remove_const_t<decltype(totest)>;                           \
    auto&& expected = [&](const auto&... vs) -> const R {                      \
      R tmp = {};                                                              \
      for (std::size_t i = 0; i < R::size(); ++i)                              \
	tmp[i] = std::name_(vs[i]...);                                         \
      return tmp;                                                              \
    };                                                                         \
    const R expect1 = expected(inputs...);                                     \
    if constexpr (std::is_floating_point_v<typename R::value_type>)            \
      {                                                                        \
	((COMPARE(isnan(totest), isnan(expect1)) << #name_ "(")                \
	 << ... << inputs)                                                     \
	  << ") = " << totest << " != " << expect1;                            \
	((where(isnan(expect1), inputs) = 0), ...);                            \
	const R expect2 = expected(inputs...);                                 \
	std::feclearexcept(FE_ALL_EXCEPT);                                     \
	asm volatile("");                                                      \
	totest = name_(inputs...);                                             \
	asm volatile("");                                                      \
	((COMPARE(std::fetestexcept(FE_ALL_EXCEPT), 0) << "\n" #name_ "(")     \
	 << ... << inputs)                                                     \
	  << ")";                                                              \
	FUZZY_COMPARE(totest, expect2);                                        \
      }                                                                        \
    else                                                                       \
      {                                                                        \
	((COMPARE(totest, expect1) << "\n" #name_ "(") << ... << inputs)       \
	  << ")";                                                              \
      }                                                                        \
  }

#endif

#define MAKE_TESTER(name_) MAKE_TESTER_2(name_, std::name_)
